From f86370295c5bb14d4bb93d0ccfa37a2b79f19f25 Mon Sep 17 00:00:00 2001
From: Philip McGrath <philip@philipmcgrath.com>
Date: Wed, 24 Aug 2022 19:55:14 -0400
Subject: [PATCH] Chez Scheme: patch s_process for "/bin/sh" on Guix

If:

    1. The nonstandard but ubiquitous macro `_PATH_BSHELL` from
       <paths.h> is defined; and

    2. The path specified by `_PATH_BSHELL` exists;

then `s_process` will call `execl` with the file specified by
`_PATH_BSHELL` instead of "/bin/sh".

Checking that the path specified by `_PATH_BSHELL` exists safeguards
against obscure errors if attempting to use stand-alone executables
built by the patched Racket in non-Guix envoronments.

This patch does not change the behavior of `s_system`, which relies
on `system` from the C library.
---
 racket/src/ChezScheme/c/prim5.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/racket/src/ChezScheme/c/prim5.c b/racket/src/ChezScheme/c/prim5.c
index 82bbf8d687..be8f603447 100644
--- a/racket/src/ChezScheme/c/prim5.c
+++ b/racket/src/ChezScheme/c/prim5.c
@@ -27,6 +27,12 @@
 #include <sys/resource.h>
 #endif
 
+/* BEGIN PATCH for Guix */
+#ifndef WIN32
+# include <paths.h>
+#endif
+/* END PATCH for Guix */
+
 /* locally defined functions */
 static INT s_errno(void);
 static IBOOL s_addr_in_heap(uptr x);
@@ -861,6 +867,17 @@ static ptr s_process(char *s, IBOOL stderrp) {
 
     INT tofds[2], fromfds[2], errfds[2];
     struct sigaction act, oint_act;
+    /* BEGIN PATCH for Guix */
+#if defined(_PATH_BSHELL)
+    struct stat guix_stat_buf;
+    char *guix_sh =
+      (0 == stat(_PATH_BSHELL, &guix_stat_buf))
+      ? _PATH_BSHELL
+      : "/bin/sh";
+#else /* _PATH_BSHELL */
+    char *guix_sh = "/bin/sh";
+#endif
+    /* END PATCH for Guix */
 
     if (pipe(tofds)) S_error("process","cannot open pipes");
     if (pipe(fromfds)) {
@@ -897,7 +914,9 @@ static ptr s_process(char *s, IBOOL stderrp) {
           }
         }
 #endif /* __GNU__ Hurd */
-        execl("/bin/sh", "/bin/sh", "-c", s, NULL);
+        /* BEGIN PATCH for Guix */
+        execl(guix_sh, guix_sh, "-c", s, NULL);
+        /* END PATCH for Guix */
         _exit(1) /* only if execl fails */;
         /*NOTREACHED*/
     } else {

base-commit: 87eee6e2adb8c6bc11e60619c706fa6295096085
-- 
2.32.0

